1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2019 Intel Corporation.
4 * Lei Chuanhua <Chuanhua.lei@intel.com>
5 */
6
7 #include <linux/bitfield.h>
8 #include <linux/init.h>
9 #include <linux/of_device.h>
10 #include <linux/platform_device.h>
11 #include <linux/reboot.h>
12 #include <linux/regmap.h>
13 #include <linux/reset-controller.h>
14
15 #define RCU_RST_STAT 0x0024
16 #define RCU_RST_REQ 0x0048
17
18 #define REG_OFFSET_MASK GENMASK(31, 16)
19 #define BIT_OFFSET_MASK GENMASK(15, 8)
20 #define STAT_BIT_OFFSET_MASK GENMASK(7, 0)
21
22 #define to_reset_data(x) container_of(x, struct intel_reset_data, rcdev)
23
24 struct intel_reset_soc {
25 bool legacy;
26 u32 reset_cell_count;
27 };
28
29 struct intel_reset_data {
30 struct reset_controller_dev rcdev;
31 struct notifier_block restart_nb;
32 const struct intel_reset_soc *soc_data;
33 struct regmap *regmap;
34 struct device *dev;
35 u32 reboot_id;
36 };
37
38 static const struct regmap_config intel_rcu_regmap_config = {
39 .name = "intel-reset",
40 .reg_bits = 32,
41 .reg_stride = 4,
42 .val_bits = 32,
43 .fast_io = true,
44 };
45
46 /*
47 * Reset status register offset relative to
48 * the reset control register(X) is X + 4
49 */
id_to_reg_and_bit_offsets(struct intel_reset_data * data,unsigned long id,u32 * rst_req,u32 * req_bit,u32 * stat_bit)50 static u32 id_to_reg_and_bit_offsets(struct intel_reset_data *data,
51 unsigned long id, u32 *rst_req,
52 u32 *req_bit, u32 *stat_bit)
53 {
54 *rst_req = FIELD_GET(REG_OFFSET_MASK, id);
55 *req_bit = FIELD_GET(BIT_OFFSET_MASK, id);
56
57 if (data->soc_data->legacy)
58 *stat_bit = FIELD_GET(STAT_BIT_OFFSET_MASK, id);
59 else
60 *stat_bit = *req_bit;
61
62 if (data->soc_data->legacy && *rst_req == RCU_RST_REQ)
63 return RCU_RST_STAT;
64 else
65 return *rst_req + 0x4;
66 }
67
intel_set_clr_bits(struct intel_reset_data * data,unsigned long id,bool set)68 static int intel_set_clr_bits(struct intel_reset_data *data, unsigned long id,
69 bool set)
70 {
71 u32 rst_req, req_bit, rst_stat, stat_bit, val;
72 int ret;
73
74 rst_stat = id_to_reg_and_bit_offsets(data, id, &rst_req,
75 &req_bit, &stat_bit);
76
77 val = set ? BIT(req_bit) : 0;
78 ret = regmap_update_bits(data->regmap, rst_req, BIT(req_bit), val);
79 if (ret)
80 return ret;
81
82 return regmap_read_poll_timeout(data->regmap, rst_stat, val,
83 set == !!(val & BIT(stat_bit)), 20,
84 200);
85 }
86
intel_assert_device(struct reset_controller_dev * rcdev,unsigned long id)87 static int intel_assert_device(struct reset_controller_dev *rcdev,
88 unsigned long id)
89 {
90 struct intel_reset_data *data = to_reset_data(rcdev);
91 int ret;
92
93 ret = intel_set_clr_bits(data, id, true);
94 if (ret)
95 dev_err(data->dev, "Reset assert failed %d\n", ret);
96
97 return ret;
98 }
99
intel_deassert_device(struct reset_controller_dev * rcdev,unsigned long id)100 static int intel_deassert_device(struct reset_controller_dev *rcdev,
101 unsigned long id)
102 {
103 struct intel_reset_data *data = to_reset_data(rcdev);
104 int ret;
105
106 ret = intel_set_clr_bits(data, id, false);
107 if (ret)
108 dev_err(data->dev, "Reset deassert failed %d\n", ret);
109
110 return ret;
111 }
112
intel_reset_status(struct reset_controller_dev * rcdev,unsigned long id)113 static int intel_reset_status(struct reset_controller_dev *rcdev,
114 unsigned long id)
115 {
116 struct intel_reset_data *data = to_reset_data(rcdev);
117 u32 rst_req, req_bit, rst_stat, stat_bit, val;
118 int ret;
119
120 rst_stat = id_to_reg_and_bit_offsets(data, id, &rst_req,
121 &req_bit, &stat_bit);
122 ret = regmap_read(data->regmap, rst_stat, &val);
123 if (ret)
124 return ret;
125
126 return !!(val & BIT(stat_bit));
127 }
128
129 static const struct reset_control_ops intel_reset_ops = {
130 .assert = intel_assert_device,
131 .deassert = intel_deassert_device,
132 .status = intel_reset_status,
133 };
134
intel_reset_xlate(struct reset_controller_dev * rcdev,const struct of_phandle_args * spec)135 static int intel_reset_xlate(struct reset_controller_dev *rcdev,
136 const struct of_phandle_args *spec)
137 {
138 struct intel_reset_data *data = to_reset_data(rcdev);
139 u32 id;
140
141 if (spec->args[1] > 31)
142 return -EINVAL;
143
144 id = FIELD_PREP(REG_OFFSET_MASK, spec->args[0]);
145 id |= FIELD_PREP(BIT_OFFSET_MASK, spec->args[1]);
146
147 if (data->soc_data->legacy) {
148 if (spec->args[2] > 31)
149 return -EINVAL;
150
151 id |= FIELD_PREP(STAT_BIT_OFFSET_MASK, spec->args[2]);
152 }
153
154 return id;
155 }
156
intel_reset_restart_handler(struct notifier_block * nb,unsigned long action,void * data)157 static int intel_reset_restart_handler(struct notifier_block *nb,
158 unsigned long action, void *data)
159 {
160 struct intel_reset_data *reset_data;
161
162 reset_data = container_of(nb, struct intel_reset_data, restart_nb);
163 intel_assert_device(&reset_data->rcdev, reset_data->reboot_id);
164
165 return NOTIFY_DONE;
166 }
167
intel_reset_probe(struct platform_device * pdev)168 static int intel_reset_probe(struct platform_device *pdev)
169 {
170 struct device_node *np = pdev->dev.of_node;
171 struct device *dev = &pdev->dev;
172 struct intel_reset_data *data;
173 void __iomem *base;
174 u32 rb_id[3];
175 int ret;
176
177 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
178 if (!data)
179 return -ENOMEM;
180
181 data->soc_data = of_device_get_match_data(dev);
182 if (!data->soc_data)
183 return -ENODEV;
184
185 base = devm_platform_ioremap_resource(pdev, 0);
186 if (IS_ERR(base))
187 return PTR_ERR(base);
188
189 data->regmap = devm_regmap_init_mmio(dev, base,
190 &intel_rcu_regmap_config);
191 if (IS_ERR(data->regmap)) {
192 dev_err(dev, "regmap initialization failed\n");
193 return PTR_ERR(data->regmap);
194 }
195
196 ret = device_property_read_u32_array(dev, "intel,global-reset", rb_id,
197 data->soc_data->reset_cell_count);
198 if (ret) {
199 dev_err(dev, "Failed to get global reset offset!\n");
200 return ret;
201 }
202
203 data->dev = dev;
204 data->rcdev.of_node = np;
205 data->rcdev.owner = dev->driver->owner;
206 data->rcdev.ops = &intel_reset_ops;
207 data->rcdev.of_xlate = intel_reset_xlate;
208 data->rcdev.of_reset_n_cells = data->soc_data->reset_cell_count;
209 ret = devm_reset_controller_register(&pdev->dev, &data->rcdev);
210 if (ret)
211 return ret;
212
213 data->reboot_id = FIELD_PREP(REG_OFFSET_MASK, rb_id[0]);
214 data->reboot_id |= FIELD_PREP(BIT_OFFSET_MASK, rb_id[1]);
215
216 if (data->soc_data->legacy)
217 data->reboot_id |= FIELD_PREP(STAT_BIT_OFFSET_MASK, rb_id[2]);
218
219 data->restart_nb.notifier_call = intel_reset_restart_handler;
220 data->restart_nb.priority = 128;
221 register_restart_handler(&data->restart_nb);
222
223 return 0;
224 }
225
226 static const struct intel_reset_soc xrx200_data = {
227 .legacy = true,
228 .reset_cell_count = 3,
229 };
230
231 static const struct intel_reset_soc lgm_data = {
232 .legacy = false,
233 .reset_cell_count = 2,
234 };
235
236 static const struct of_device_id intel_reset_match[] = {
237 { .compatible = "intel,rcu-lgm", .data = &lgm_data },
238 { .compatible = "intel,rcu-xrx200", .data = &xrx200_data },
239 {}
240 };
241
242 static struct platform_driver intel_reset_driver = {
243 .probe = intel_reset_probe,
244 .driver = {
245 .name = "intel-reset",
246 .of_match_table = intel_reset_match,
247 },
248 };
249
intel_reset_init(void)250 static int __init intel_reset_init(void)
251 {
252 return platform_driver_register(&intel_reset_driver);
253 }
254
255 /*
256 * RCU is system core entity which is in Always On Domain whose clocks
257 * or resource initialization happens in system core initialization.
258 * Also, it is required for most of the platform or architecture
259 * specific devices to perform reset operation as part of initialization.
260 * So perform RCU as post core initialization.
261 */
262 postcore_initcall(intel_reset_init);
263